bagging, (Informal) the artificial ventilation performed with a respirator bag, such as a bag-valve-mask resuscitator (Ambu bag) or the reservoir bag on an anesthesia machine. The bag is squeezed to deliver positive pressure gases to the patient’s lungs through a mask, an endotracheal tube, a laryngeal mask, or another breathing device. During general anesthesia, the anesthetist may use this technique to assist or control the respiration of an unconscious patient.